There has been conventionally developed an image processing system in which an image input device such as a video camera is connected to a general-purpose calculator such as a personal computer or a work station so that image data input from the image input device is processed in the calculator. The calculator in such an image processing system is provided with plural image processing objects for performing image processing such as color detection or motion detection, thereby subjecting the input image data to plural image processing.
Consequently, in the calculator in the image processing system, the image data input from the image input device is temporarily stored in a frame buffer, and then, the image data is transferred from the frame buffer to a memory, to which a CPU (Central Processing Unit) for executing each of the image processing objects can directly make access, or the image data is read by direct access of each of the image processing objects to the frame buffer.
Alternatively, besides the image processing system in which the image input device is connected to the general-purpose calculator, there has been developed an incorporation type image processing apparatus in which an image input device is previously incorporated in a general-purpose calculator. Such an incorporation type image processing apparatus includes a DSP (Digital Signal Processor) for executing specific image processing, is configured such that single image processing can be performed at a high speed by directly writing image data in a memory in the DSP.
In the image processing system in which the image input device is connected to the general-purpose calculator, a time taken for transferring the image data is liable to be increased in proportion to the number of image processing objects which are executed by the CPU, with an attendant problem of a long time required for the image processing. Incidentally, a method for temporarily storing the image data in the frame buffer to then transfer it to the memory is disclosed in, for example, Japanese Patent Laid-open No. 8-297585. However, this method raises problems that a transferring speed becomes low by a time required for temporarily storing the image data in the frame buffer, and further, that the CPU cannot perform other processing till the completion of the data transfer since the CPU transfers the data. Moreover, a method for reading the image data by direct access by each of the image processing objects to the frame buffer raises problems that portability is poor since the CPU directly makes access to the frame buffer as hardware and that safety of data protection cannot be secured, in addition to slow access to the data.
On the other hand, the incorporation type image processing apparatus uses the DSP which can perform only specific image processing, thereby making it difficult to simultaneously perform plural image processing or write a program independent of hardware.